The present invention relates to computer implemented methods of obtaining a dataset answering a query from a relational database. The invention is particularly, although not exclusively, directed to methods of obtaining such a dataset using a structured query language (SQL).
A relational database is a commonly used form of database in which information is stored and accessed via so-called base “relations”, which, in implementations, are in the form of tables having rows and columns. In typical arrangements, the rows of the table represent records, each row being a structured set of related information about a given item, and the columns represent fields or attributes of the rows.
Ever increasing amounts of data are collected, and organised into relational databases. There is correspondingly an increasing need to be able to effectively query the data held in such databases to obtain datasets of interest. When querying a relational database, a database query language is used. One particularly well known example of such a language is the structured query language (SQL), which may also be used in performing other functions in relation to the database, e.g. updating and managing the database.